During the Christmas season, people are used to bringing the Christmas trees into their homes or shopping centers, decorating them with strings of lights and ornaments. However, to decorate a real pine causes quite a lot of trouble, so for convenience, people prefer an artificial pine, and manufacturers always tie strings of lights in the artificial pine boles as ornaments. Mostly, the artificial pine is disassembled into two to four boles so as to be packaged in boxes, each bole has many preinstalled decorative string lights, and electric connectors are usually exposed outside bole leaves. Customers have to assemble the boles and connect the adjacent electric connectors of the decorative lights of each bole so as to power on the lights in the whole tree. While partly due to the redundant string lights of each bole, the customers feel troublesome and take much time to match all the electric connectors of the string lights. Therefore, use is quite inconvenient. What's worse, if the electric connectors are arranged in the boles, it is almost unlikely to maintain the electronic part of the electronic connectors or electric wires in the lights of the boles. For instance, disconnection of only one light circuit or a connector in a metal bole may result in blackout of all the lights in the tree. It is very hard to maintain, or even the entire bole should be partially or integrally replaced.